@Wolfraing
Not really, and spirits not really that far from gods. Didn't you saw how garden folks deify spirit lady of the MC?
They are part of the nature force, and closest thing to the god. So, just think about that they might think that size of the rainbow comes from the power and hierarchy of the gods etc
In the next chapter we will learn what exactly they think about rainbow in details, but i can say something right now for sure. There is NO WAY that they would think that microscopic water droplets "levitate" through the air, and there is no way that they know about light dispersion, it's still not the time for them.
The only thing that they can actually assume, that rainbow have connection with "water", like rain or watersource. Sure, but does it make any less divine? Nope.
Water is miracle of life on their own right, and gods using water and rain to build a god bridge from the light itself, that can't be "touched" by the resident of the mortal world. Small rainbow can be also described as "covert actions" of gods that want to play pranks etc.
It's not pushing too far, you just trying to assume things based on relatively"new" knowledge that their world isn't supposed to have. You yourself wouldn't say "it's just a rainbow" too, if you wouldn't convenietly knew beforehand how it's produced.
Just saying, our own mythology also have tons of rainbow "interpretations", it's quite unfair to just brush it off like it's nothing that big and they are fools, when "law" that created it actually quite complicated.